GDK_GL_DEPTH_SIZE value of GtkGlArea widget

[Abhir Joshi <abhir@vsnl.net>]

While creating a GtkGlArea widget a number of attributes need to be
specified.  One of them is GDK_GL_DEPTH_SIZE.  I still don't know what
exactly does this mean.  On my machine (that doesn't have hardware
acceleration) if I set this value to 16, surfaces don't get rendered
properly.  Some hidden parts are visible and some visible parts get
hidden.  I observed that it becomes dependent on the order of
rendering those surfaces.  If I increase the depth size to 24, things
become a bit better.  If I set the value around 100, the surfaces are
rendered perfectly.

Now when I try to run this program on a machine having i810
motherboard with h/w acceleration and depth size set to 16, the
surfaces aren't rendered properly.  This is the same thing that
happens on my machine.  But now if I increase the depth value to
anything above 16, it fails to create the GtkGlArea widget itself.
The depth value of X is 16 for all the time.

When directly using GLUT with depth value of 16, there are no problems
at all on machines with or without h/w acceleration.

What could be going wrong?  Am I missing on some other parameter?


-- 
Abhir Joshi
http://education.vsnl.com/abhir/